Hello I have had this External HD for 4 years now, it worked fine to drop and save my video and music files. So I decided to clear some space to make room for more back up files and deleted what I saw in the finder for this drive. However now when I go to back up I keep getting "not enough disk space" I see of the 160GB I only have 9GB available.

How do I clear what I can't see? In my finder for this drive i show no files or folders..